Turn-fin tube, manufacturing apparatus of the turn-fin tube, manufacturing method of the turn-fin tube and turn-fin  type heat exchanger using the turn-fin tube

ABSTRACT

A turn-fin tube, a turn-fin type heat exchanger using the same, and an apparatus and method for manufacturing the same are provided. The turn-fin tube includes a tube in which a fluid flows, and a fin wound on an outer surface of the tube in a helical shape. The fin includes a base section wound on an outer surface in contact with the tube, and an extension section extending from the base section in an outward direction of the tube at a predetermined angle.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of Korean Patent Applications No. 10-2009-0035576, filed on Apr. 23, 2009 and No. 10-2009-0035577, filed on Apr. 23, 2009 and all the benefits accruing therefrom under 35 U.S.C. §119 which is hereby incorporated by references as if fully set forth herein.

BACKGROUND

1. Field

The disclosure generally relates to a turn-fin tube, an apparatus and method for manufacturing the same, and a turn-fin type heat exchanger using the same and, more particularly, to a turn-fin tube and a turn-fin type heat exchanger using the same, both of which are easily machined and can increase heat efficiency, and an apparatus and method for manufacturing the turn-fin tube, capable of reducing a fraction defective as well as the cost of production in manufacturing the turn-fin tube.

2. Description of the Related Art

Heat exchangers generally exchange heat between a refrigerant flowing inside tubes and a fluid such as air or cooling water outside the tubes.

One such heat exchanger is a condenser, which condenses and liquefies the refrigerant by radiating heat of the refrigerant, i.e. high-temperature high-pressure gas, discharged from a compressor to the fluid such as air or cooling water under room temperature.

Condensers are classified as wire types and turn-fin types according to their shapes. Here, the turn-fin type condenser is composed of a tube in which the refrigerant flows, and fins wound around the tube to enhance a surface area for exchanging heat between the refrigerant inside the tube and the fluid such as air or cooling water outside the tube.

However, the fins installed on the conventional turn-fin tube have the shape of a thin sheet. As such, an area where the fins are in close contact with the tube is small, which leads to a small heat transfer area. Consequently, the fins have a structural limitation in improving heat transfer efficiency. For this reason, there is a need for the fins to be designed in a new shape, and an apparatus and method of manufacturing such a turn-fin tube

SUMMARY

Exemplary embodiments provide a turn-fin tube capable of providing excellent machinability and increasing heat transfer efficiency, a turn-fin type heat exchanger using the same, and an apparatus and method for manufacturing the same.

Exemplary embodiments provide an apparatus and method for manufacturing a turn-fin tube, capable of reducing a fraction defective as well as the cost of production in manufacturing the turn-fin tube.

Exemplary embodiments provide a turn-fin tube capable of reducing the height of a fin and stably joining the fin with a tube, and a turn-fin type heat exchanger using the same.

According to an exemplary embodiment, a turn-fin tube includes: a tube in which a fluid flows; and a fin wound on an outer surface of the tube in a helical shape. The fin includes a base section wound on an outer surface in contact with the tube, and an extension section extending from the base section in an outward direction of the tube at a predetermined angle.

Here, the tube may have a helical groove dented in a helical shape in a lengthwise direction thereof, and the base section is fitted into the helical groove.

Further, the extension section may include a first extension section, which extends in the outward direction of the tube, and a second bending section, which is bent at the first extension section in a lengthwise direction of the tube, on a tube bending section.

In addition, the extension section located on a tube bending section where the tube is bent may be installed in the state in which at least a part thereof is cut off.

According to another exemplary embodiment, an apparatus for manufacturing a turn-fin tube includes: a tube supplying unit supplying a hollow tube; a strip supply unit supplying a strip; and a groove forming unit forming the strip into a fin wound on an outer surface of the tube in a helical shape. The fin includes a base section installed on the outer surface in contact with the tube, and an extension section extending from the base section in an outward direction of the tube at a predetermined angle.

Here, the apparatus tube may further include a groove forming unit, which presses the outer surface of the tube to form a helical groove in a lengthwise direction of the tube such that the base section can be fitted into the helical groove.

Further, the apparatus tube may further include a pressing unit, which presses the extension section located on a tube bending section where the tube is bent so as to have a first extension section, which extends from the base section in an outward direction of the tube at a predetermined angle, and a second bending section, which is bent at the first extension section in a lengthwise direction of the tube.

The groove forming unit may include: a pressing roller having a pressing blade pressing the tube to form the helical groove in the lengthwise direction of the tube that is rotated and linearly transferred; and a supporting roller assembly having supporting rollers, which are rotated corresponding to a rotational direction of the tube and support the tube on one diametrical side of the tube when the pressing blade presses the tube on the other diametrical side of the tube while being rotated.

Further, the groove forming unit may further include a roller assembly moving unit, which moves the supporting roller assembly in a vertical direction.

The groove forming unit may further include a tilting unit, which tilts the pressing blade to change a contact angle between the pressing blade and the outer surface of the tube.

Further, the apparatus may further include a cutting unit cutting at least a part of the extension section located on a tube bending section where the tube is bent.

According to still another exemplary embodiment, a method of manufacturing a turn-fin tube includes: supplying a hollow tube; supplying a strip; forming the strip into a fin, the fin having a base section installed on an outer surface in contact with the tube and an extension section extending from the base section in an outward direction of the tube at a predetermined angle; and winding the fin on the outer surface of the tube to form the turn-fin tube.

Further, the method may further include pressing the outer surface of the tube to form a helical groove in a lengthwise direction of the tube such that the base section can be fitted into the helical groove.

The method may further include pressing the extension section located on a tube bending section where the tube is bent so as to have a first extension section, which extends from the base section in an outward direction of the tube at a predetermined angle, and a second bending section, which is bent at the first extension section in a lengthwise direction of the tube.

The forming of the helical groove may include: rotating and linearly transferring the tube; bringing supporting rollers, which are rotated corresponding to a rotational direction of the tube, in contact with on a diametrical upper outer surface of the tube; and pressing a diametrical lower outer surface of the tube using a rotating pressing blade in order to press the tube to form a helical groove in a lengthwise direction of the tube.

Further, the forming of the helical groove may further include tilting the pressing blade to change a contact angle between the pressing blade and the outer surface of the tube.

The method may further include cutting at least a part of the extension section located on a tube bending section where the tube is bent.

According to yet another exemplary embodiment, a turn-fin type heat exchanger includes: the turn-fin tube having a tube in which a fluid flows; and a fin wound on an outer surface of the tube in a helical shape; and a bracket supporting the turn-fin tube.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments are described in further detail below with reference to the accompanying drawings. It should be understood that various aspects of the drawings may have been exaggerated for clarity:

FIG. 1 is a block diagram illustrating construction of an apparatus for manufacturing a turn-fin tube according to an exemplary embodiment;

FIG. 2 is a schematic plan view illustrating construction of the turn-fin tube manufacturing apparatus of FIG. 1;

FIG. 3 sequentially illustrates processes of manufacturing a first example of a turn-fin tube using the turn-fin tube manufacturing apparatus of FIG. 1;

FIG. 4 sequentially illustrates processes of manufacturing a second example of a turn-fin tube using the turn-fin tube manufacturing apparatus of FIG. 1;

FIG. 5 sequentially illustrates processes of manufacturing a third example of a turn-fin tube using the turn-fin tube manufacturing apparatus of FIG. 1;

FIG. 6 is a cross-sectional view of a preliminary fin forming unit of a fin forming unit installed on the turn-fin tube manufacturing apparatus of FIG. 2;

FIG. 7 is a cross-sectional view illustrating a final fin forming unit of a fin forming unit installed on the turn-fin tube manufacturing apparatus of FIG. 2;

FIG. 8 is a side cross-sectional view illustrating a groove forming unit installed on the turn-fin tube manufacturing apparatus of FIG. 2;

FIG. 9 is a front cross-sectional view illustrating an important part of a groove forming unit installed on the turn-fin tube manufacturing apparatus of FIG. 2;

FIG. 10 is a cross-sectional view illustrating the state before the extension section of a fin is formed by a pressing unit installed on the turn-fin tube manufacturing apparatus of FIG. 2; and

FIG. 11 is a cross-sectional view illustrating the state in which the extension section of a fin is being formed by a pressing unit installed on the turn-fin tube manufacturing apparatus of FIG. 2.

DETAILED DESCRIPTION

Various exemplary embodiments will now be described more fully with reference to the accompanying drawings in which some exemplary embodiments are shown. In the drawings, the thicknesses of layers and regions may be exaggerated for clarity.

FIG. 1 is a block diagram illustrating construction of an apparatus for manufacturing a turn-fin tube according to an exemplary embodiment. FIG. 2 is a schematic plan view illustrating construction of the turn-fin tube manufacturing apparatus of FIG. 1. FIG. 3 sequentially illustrates processes of manufacturing a first example of a turn-fin tube using the turn-fin tube manufacturing apparatus of FIG. 1.

Referring to FIGS. 1 through 3, an apparatus for manufacturing a turn-fin tube according to an exemplary embodiment includes a strip supplying unit 100 supplying a strip 10 having the shape of a flat sheet, a fin forming unit 400 forming the strip 10 into a fin 13 having a base section 11 and an extension section 12, a cutting unit 900 cutting a part of the extension section 12, a tube supplying unit 500 supplying a tube 20, a groove forming unit 600 forming a helical groove 21 in an outer surface of the tube 20, and a rolling unit 700 rolling the extension section 12 to separate the part of the extension section 12.

The strip 10 is a flat metal sheet having a long length and a narrow width, and the tube 200 is a hollow tube in which a fluid can flow.

The strip supplying unit 100 includes a plurality of guide rollers 121 and 122 disposed in a direction in which the strip 10 is supplied, and a direction conversion roller 123 installed on a portion where the direction in which the strip 10 is supplied is changed. Consequently, the strip 10 moves along the guide rollers 121 and 122 and the direction conversion roller 123 to be supplied into the fin forming unit 400.

The fin forming unit 400 includes a preliminary fin forming unit 200 and a final fin forming unit 300, both of which are sequentially disposed in the direction in which the strip 10 is supplied in order to form the strip 10 into the fin 13 having the base section 11 and the extension section 12. Here, a bending angle of the base section 11 bent by the final fin forming unit 300 may be greater than that of the base section 11 bent by the preliminary fin forming unit 200.

Thus, the fin forming unit 400 forms the strip 10 supplied by the strip supplying unit 100 into the fin 13, for instance an L-shaped fin, having the base section 11 fitted into the helical groove 21 of the tube 20 and the extension section 12 extending from the base section 11 outward in a radial direction of the tube 20 at a predetermined angle. A process of forming the strip 10 into the L-shaped fin 13 using the fin forming unit 400 will be described below in detail.

The cutting unit 900 cuts a tear-off notch 14 in the part of the extension section 12 of the fin 13 in a lengthwise direction of the fin 13. The extension section 12 of the fin 13 having the tear-off notch 14 formed by the cutting unit 900 is rolled by the rolling unit 700, and thus the part of the extension section 12 located under the tear-off notch 14 is separated off. That is, the fin 13 disposed on a tube bending section 20 a is composed of the base section 11 and the cut extension section 12 c.

In the exemplary embodiment, the part of the extension section 12 has been described as being incompletely cut off by the cutting unit 900. Alternatively, the part of the extension section 12 may be completely cut off by the cutting unit 900.

The rolling unit 700 includes first and second roller assemblies 710 and 720, which are disposed on both sides of the transferred extension section 12 and roll the extension section 12. Here, the extension section 12 may pass between the first and second roller assemblies 710 and 720 to form corrugation.

The extension section 12 is corrugated because a first roller of the first roller assembly 710 and a second roller of the second roller assembly 720 are controlled to have different rotational speeds by a control unit (not shown).

Consequently, the rolling unit 700 functions to roll and cut off the part of the extension section 12 as well as to corrugate the extension section 12.

Meanwhile, the turn-fin tube manufacturing apparatus further includes a fin guide unit 420, which guides the fin 13 to the rolling unit 700 in position and supports the fin 13. The turn-fin tube manufacturing apparatus further includes a strip guide unit 410, which guides the strip 10 to the fin forming unit 400 in position.

Thus, the strip guide unit 410 and the fin guide unit 420 make it possible to form the strip 10 into the L-shaped fin 13 having the base and extension sections 11 and 12 in a stable, smooth manner.

Meanwhile, while the strip 10 having a flat sheet shape is being formed into the fin 13 and being transferred to the rolling unit 700, the tube 20 is supplied to the groove forming unit 600 by the tube supplying unit 500, is machined by the groove forming unit 600, and then is supplied adjacent to the rolling unit 700.

The groove forming unit 600 presses an outer surface of the tube 20 to form a helical groove 21 in the outer surface of the tube 20. In detail, the outer surface of the tube 20 is dented, along with an inner surface of the tube 20, so that the helical groove 21 is formed in the outer surface of the tube 20, and a helical ridge 23 is formed in the inner surface of the tube 20. The helical ridge 23 formed in the inner surface of the tube 20 causes a fluid inside the tube 20 to form a vortex, so that it is possible to enhance the efficiency of heat exchange between the fluid inside the tube and the fin. The base section 11 of the fin 13 is fitted into the helical groove 21 of the tube 20, so that it is wound on the outer surface of the tube 20 in a helical shape. Thereby, a turn-fin tube is obtained.

In the apparatus for manufacturing a turn-fin tube according to an exemplary embodiment, the tube 20 and the fin 13 are simultaneously machined by different forming units. In detail, the fin 13 is machined by the fin forming unit 400 through a process of forming the fin so as to have the base section 11 contacting the tube 20 and the extension section 12 extending from the base section 11 in an outward direction of the tube 20 at a predetermined angle, and simultaneously the tube 20 is machined by the groove forming unit 600 that forms the helical groove 21 in the outer surface of the tube.

Here, the fin forming process includes a primary bending process of primarily bending the strip 10 having a flat sheet shape to form the base section 11 using the preliminary fin forming unit 200, and a secondary bending process of bending the base section 11 undergoing the primary bending process using the final fin forming unit 300. As a result, the fin is substantially L-shaped.

Afterwards, the extension section 12 of the fin 13 passes through the rolling unit 700, thereby being rolled by the first and second roller assemblies 710 and 720 that are rotated on both sides thereof.

Here, the fin 13 passing through the rolling unit 700 is wound on the outer surface of the tube 20 in a helical shape. In detail, the base section 11 of the fin 13 is fitted into the helical groove 21 of the tube 20, so that the fin 13 is wound on the outer surface of the tube 20. Thereby, the turn-fin tube is formed.

Before the process of winding the fin 13 on the outer surface of the tube 20, the base section 11 of the fin 13 may be joined to the outer surface of the tube 20 by brazing or an adhesive at first.

Since the tube 20 is rotated when linearly transferred, the fin 13 is helically wound on the outer surface of the tube 20. In this case, if the speed at which the tube 20 is linearly transferred is not constant or is variable, a pitch of the wound fin 13 may be non-uniform.

Consequently, the first example of the turn-fin tube manufactured by the turn-fin tube manufacturing apparatus includes the tube in which a fluid flows, and the fin wound on the outer surface of the tube in a helical shape. The fin has the base section 11 wound on the outer surface in contact with the tube, and the extension section 12 extending from the base section 11 in an outward direction of the tube at a predetermined angle. Here, the tube has the helical groove 21 that is dented in a helical shape in a lengthwise direction. The base section 11 is fitted into the helical groove 21.

The extension section located on the bending section 20 a where the tube is bent is installed in the state in which at least a part thereof is cut off.

Further, a turn-fin heat exchanger includes such a turn-fin tube and a bracket (not shown) supporting the turn-fin tube.

A second example of the turn-fin tube manufactured by the turn-fin tube manufacturing apparatus will be described with reference to FIGS. 1, 2 and 4.

Unlike the first example of the turn-fin tube, the second example of the turn-fin tube is configured such that the extension section 12 of the fin is installed on the tube bending section 20 a, which is a region where the turn-fin tube is bent, in a bent state without being cut off.

Consequently, in manufacturing the second example of the turn-fin tube, no cutting unit is used, and a pressing unit 800 is used to press the extension section of the fin located on the bending section.

The pressing unit 800 includes a pressing member (see 810 of FIG. 10) pressing the extension section 12 to form first and second extension sections 12 a and 12 b, and a driver (not shown) driving the pressing member.

When the turn-fin tube is transferred, a portion where the turn-fin tube is to be bent by the pressing unit 800, that is, the extension section 12 located on the tube bending section 20 a is formed into the first and second extension sections 12 a and 12 b.

The first extension section 12 a is formed so as to have an inclined angle at which it extends from the base section 11 of the fin in an outward direction of the tube, and the second extension section 12 b is bent at the first extension section 12 a in a lengthwise direction of the tube 20.

Consequently, before the turn-fin tube is bent, the second extension section 12 b of the extension section 12 located on the tube bending section 20 a is previously bent. Thereby, when the turn-fin tube is bent, it is possible to reduce a bending load applied to the tube bending section 20 a, so that the tube 20 or the fin 13 can be prevented from being crushed or damaged. Further, by previously bending the second extension section 12 b, it is possible to fix the turn-fin tube to the bracket without causing damage to the fin.

Alternatively, the extension section may be cut off to reduce the bending load when the turn-fin tube is bent. However, since the extension section is not cut off in the exemplary embodiment, it is possible to increase heat transfer efficiency as well as machinability.

An operation time of the pressing unit 800 is pre-stored in a control unit (not shown), so that the pressing unit 800 can be operated when the tube bending section 20 a, that is, the region where the turn-fin tube is bent arrives at the pressing unit 800.

Consequently, the second example of the turn-fin tube manufactured by the turn-fin tube manufacturing apparatus includes the tube in which a fluid flows, and the fin wound on the outer surface of the tube in a helical shape. The fin has the base section wound on the outer surface in contact with the tube, and the extension section extending from the base section in an outward direction of the tube at a predetermined angle. Here, the tube has the helical groove that is dented in a helical shape in a lengthwise direction. The base section is fitted into the helical groove.

The extension section located on the bending section where the tube is bent has the first extension section extending in an outward direction of the tube, and the second extension section bent at the first extension section in a lengthwise direction of the tube.

A third example of the turn-fin tube manufactured by the turn-fin tube manufacturing apparatus will be described with reference to FIGS. 1, 2 and 5.

Unlike the second example of the turn-fin tube, the third example of the turn-fin tube is configured such that the base section 11 of the fin is wound on the outer surface of the tube 20. In detail, since the third example of the turn-fin tube has no helical groove, the base section 11 of the fin is installed on the outer surface of the tube 20.

Consequently, in the turn-fin tube manufacturing apparatus for the third example of the turn-fin tube, the groove forming unit forming the helical groove in the outer surface of the tube, and the cutting unit cutting the part of the extension section of the fin are not used.

The preliminary fin forming unit of the fin forming unit according to an exemplary embodiment will be described in detail with reference to FIGS. 2 and 6.

The preliminary fin forming unit 200 includes first and second preliminary fin forming roller assemblies 210 and 220 installed spaced apart from each other by a predetermined interval, and a preliminary fin forming interval adjuster 230 adjusting an interval between the first and second preliminary fin forming roller assemblies 210 and 220.

The first preliminary fin forming roller assembly 210 includes a first preliminary fin forming roller 211 rotated in close contact with the transferred strip 10, a first preliminary fin forming roller shaft 214 forming a central axis of rotation of the first preliminary fin forming roller 211, a first preliminary fin forming roller frame 215 supporting the first preliminary fin forming roller shaft 214, and a first preliminary fin forming roller bearing 213 installed between the first preliminary fin forming roller 211 and the first preliminary fin forming roller shaft 214.

Similarly, the second preliminary fin forming roller assembly 220 includes a second preliminary fin forming roller 221 rotated in close contact with the transferred strip 10, a second preliminary fin forming roller shaft 224 forming a central axis of rotation of the second preliminary fin forming roller 221, a second preliminary fin forming roller frame 225 supporting the second preliminary fin forming roller shaft 224, and a second preliminary fin forming roller bearing 223 installed between the second preliminary fin forming roller 221 and the second preliminary fin forming roller shaft 224.

Here, the first and second preliminary fin forming rollers 211 and 221 are installed in a stepwise fashion in such a manner that an upper end of the second preliminary fin forming roller 221 is by a predetermined distance lower than that of the first preliminary fin forming roller 211. The base section 11 of the fin is formed between the upper ends of the first and second preliminary fin forming rollers 211 and 221.

In detail, the first preliminary fin forming roller 211 has a first roller wedge 211 a protruding from the upper end thereof at a first inclined angle x1, whereas the second preliminary fin forming roller 221 has a cylindrical shape in whole.

Consequently, the fin passes between the upper ends of the first and second preliminary fin forming rollers 211 and 221 to be bent at a first inclined angle x1, so that the base section 11 of the fin is formed.

The preliminary fin forming interval adjuster 230 includes a first positioning block 216 installed under the first preliminary fin forming roller assembly 210, and a first interval adjusting bolt 231 screwed to the first positioning block 216.

The first positioning block 216 is displaced in a horizontal direction by turning the first interval adjusting bolt 231. The displacement of the first positioning block 216 causes the first preliminary fin forming roller assembly 210 coupled to the first positioning block 216 to be displaced in a horizontal direction.

Consequently, as the first preliminary fin forming roller assembly 210 is displaced in a horizontal direction, the interval between the first and second preliminary fin forming rollers 211 and 221 is adjusted.

The final fin forming unit of the fin forming unit according to an exemplary embodiment will be described in detail with reference to FIGS. 2 and 7.

The final fin forming unit 300 includes first and second final fin forming roller assemblies 310 and 320 installed spaced apart from each other by a predetermined interval, and a final fin forming interval adjuster 330 adjusting an interval between the first and second final fin forming roller assemblies 310 and 320.

The first final fin forming roller assembly 310 includes a first final fin forming roller 311, a first final fin forming roller shaft 314, a first final fin forming roller frame 315, and a first final fin forming roller bearing 313, and the second final fin forming roller assembly 320 includes a second final fin forming roller 321, a second final fin forming roller shaft 324, a second final fin forming roller frame 325, and a second final fin forming roller bearing 323. Further, the final fin forming interval adjuster 330 includes a second positioning block 316 installed under the first final fin forming roller assembly 310, and a second interval adjusting bolt 331 screwed to the second positioning block 316. A detailed description of these components is omitted since they are similar to those of the preliminary fin forming unit 200.

However, the first final fin forming roller 311 is provided with a roller groove 311 a corresponding to the extension section 12 of the fin, and a second roller wedge 311 b protruding from an upper end thereof at a second inclined angle x2.

Here, the first and second final fin forming rollers 311 and 321 are installed in a stepwise fashion in such a manner that an upper end of the second final fin forming roller 321 is by a predetermined distance lower than that of the first final fin forming roller 311. The base section 11 of the fin is formed between the upper ends of the first and second final fin forming rollers 311 and 321.

Consequently, the fin passes between the upper ends of the first and second final fin forming rollers 311 and 321 to be formed into the extension section 12 of the fin by the roller groove 311 a and the base section 11 of the fin by an interval between the second roller wedge 311 b of the first final fin forming roller 311 and the upper end of the second final fin forming roller 321.

Here, the bending angle x2 of the base section formed by the final fin forming unit 300 is greater than that x1 of the base section formed by the preliminary fin forming unit 200.

The groove forming unit of the fin forming unit according to an exemplary embodiment will be described in detail with reference to FIGS. 2, 8 and 9.

The groove forming unit 600 includes a pressing roller assembly 630 forming the helical groove in the tube and having a pressing blade 631 and a pressing roller 632, and a supporting roller assembly 620 rotatably supporting the tube 20 on one diametrical side of the tube 20 when the pressing blade 631 presses the tube 20 on the other diametrical side of the tube 20 while being rotated.

The groove forming unit 600 further includes a roller assembly moving unit 610 moving the supporting roller assembly 620 in a vertical direction, and a tilting unit 640 tilting the pressing blade 631 to change a contact angle between the pressing blade 631 and the tube 20.

The pressing roller assembly 630 includes a driving motor (not shown), and a pressing roller shaft 633 rotated by the driving motor, in addition to both the pressing roller 632 coupled with the pressing roller shaft 633 and the pressing blade 631 that is formed on an outer circumference of the pressing roller body 632 and comes into contact with the outer surface of the tube 20.

When the driving motor rotates, the pressing roller shaft 633 is rotated. When the pressing roller shaft 633 is rotated, the pressing roller 632 is rotated. When the pressing blade 631 formed on the pressing roller 632 is rotated, the pressing blade 631 presses the outer surface of the tube 20.

Thereby, the outer surfaces of the tube 20 is dented, along with the inner surface of the tube 20, so that the helical groove 21 is formed in the outer surface of the tube 20, and the helical ridge 23 is formed on the inner surface of the tube 20. The base section 11 of the fin is fitted into the helical groove 21, and thus the fin 13 is prevented from running idle on the outer surface of the tube 20, so that the fin 13 can be stably joined with the tube 20.

The supporting roller assembly 620 includes supporting rollers 622 disposed opposite to the pressing blade 631, roller shafts 621 having the centers of rotation of the supporting rollers 622, and a supporting block 623 coupled with the roller shafts 621 and supporting the roller shafts 621.

Here, the supporting rollers 622 are installed in parallel on a diametrical upper outer surface of the tube, and are rotated in a direction where the tube is rotated and displaced.

The roller assembly moving unit 610 includes a movable frame 615 coupled with the supporting block 623, a coupler 614 coupling the movable frame 615 with the supporting block 623, a pneumatic cylinder 611 moving the movable frame 615, a bushing 613 displaced by the pneumatic cylinder 611 and guiding the movement of the movable frame 615, and a guide shaft 612.

When the pneumatic cylinder 611 is operated, the bushing 613 is vertically displaced, and thus the movable frame 615 moves up and down. Then, the supporting block 623 coupled with the movable frame 615 is displaced, so that the supporting rollers 622 installed on the supporting block 623 are displaced in a vertical direction. Thus, an interval between the supporting rollers 622 and the pressing blade 631 is adjusted by the vertical displacement of the supporting rollers 622.

The tilting unit 640 includes a worm wheel (not shown) coupled with the pressing blade 631, a worm shaft 643 coupled to the worm wheel, a rotating shaft 642 rotating the worm shaft 643, and a handle 641 rotating the rotating shaft 642.

When the handle 641 is turned by a user, the rotating shaft 642 is rotated, and thus the worm shaft 643 is rotated. When the worm shaft 643 is rotated, the worm wheel is rotated to tilt the pressing blade 631 contacting the tube 20. As a result, a contact angle at which the pressing blade 631 is in contact with the outer surface of the tube 20 is changed.

Further, the groove forming unit 600 may further include a pressing roller moving unit 650 moving the pressing roller assembly 630 in a vertical direction. The pressing roller moving unit 650 functions to adjust the interval between the supporting rollers 622 and the pressing roller 632. The interval between the supporting rollers 622 and the pressing roller 632 may be adjusted by the vertical displacement of the supporting roller assembly 620 or the pressing roller 632.

A process of manufacturing the turn-fin tube using the groove forming unit of the turn-fin tube manufacturing apparatus will be simply described below.

When the tube 20 is supplied in a rotational and linear motion by the tube supplying unit 500, the groove forming unit 600 presses the tube 20 to form the helical groove 21 in a lengthwise direction of the tube 20.

When the helical groove 21 is formed in the tube 20, the supporting roller assembly 620 having the supporting rollers 622 rotated corresponding to the rotational direction of the tube 20 contacts and presses an upper outer surface of the tube 20. Then, the pressing blade 631 presses a diametrical lower outer surface of the tube to form the helical groove 21 in the tube 20 in the lengthwise direction of the tube 20.

At this time, when a contact angle between the tube 20 and the pressing blade 631 is to be changed, the pressing blade 631 may be tilted using the tilting unit 640.

Meanwhile, the supplied strip is formed into the fin 13 having the base section fitted into the helical groove 21 and the extension section 12 extending from the base section 11 in an outward direction of the tube 20 at a predetermined angle.

Then, the fin 13 passes through the rolling unit 700, and thus the base section 11 of the fin is wound in the helical groove 21 of the tube in a helical shape. Thereby, the turn-fin tube is formed.

Consequently, the helical groove 21, into which the base section 11 of the fin is fitted, is formed in the outer surface of the tube 20, so that it is possible to reduce an entire height of the turn-fin tube. Further, the base section 11 of the fin is in a surface contact with the helical groove 21 of the tube, so that a surface contact area is increased to enhance the heat-exchange efficiency.

A process of pressing the turn-fin tube using the pressing unit of the turn-fin tube manufacturing apparatus will be described with reference to FIGS. 10 and 11.

The pressing unit 800 according to an exemplary embodiment includes a pressing member 810 pressing the extension section 12 of the fin, and a driver (not shown) driving the pressing member 810. Further, the pressing unit 800 presses a tube bending section, that is a region where the turn-fin tube is to be previously bent, to form the extension section 12 of the fin into first and second extension sections 12 a and 12 b.

In detail, the pressing member 810 moves in a radial direction of the turn-fin tube to press the extension section 12 of the fin, and simultaneously moves in a lengthwise direction of the turn-fin tube to press the extension section 12 of the fin. Here, an inner surface of the pressing member 810 is formed at an inclined angle such that the extension section 12 of the fin is smoothly bent in a lengthwise direction of the tube 20.

When the pressing member 810 presses the extension section 12 of the fin, an end of the extension section 12 contacting the pressing member 810 begins to be bent in the lengthwise direction of the tube 20 by the inclined angle of the inner surface of the pressing member 810. When the extension section is bent to some extent, the pressing member 810 moves in the lengthwise direction of the tube 20 to press the extension section 12 again. Of course, the tube may move toward the pressing member in the lengthwise direction.

Consequently, the extension section 12 of the fin is formed into the first extension section 12 a bent so as to have a predetermined angle with respect to the base section 11, and the second extension section 12 b extending from the first extension section 12 a and bent in the lengthwise direction of the tube. Alternatively, a manufacturer may directly bend the extension section by hand without using the pressing member to bend the extension section to form the first and second extension sections 12 a and 12 b.

A turn-fin tube, a turn-fin type heat exchanger using the turn-fin tube, and an apparatus and method for manufacturing the turn-fin tube according to exemplary embodiments have the following effects.

First, the helical groove, into which the base section of the fin, is formed in the outer surface of the tube, so that the entire height of the turn-fin tube can be reduced. Further, if the entire height of the turn-fin tube is set to the same height as a known turn-fin tube, it is possible to increase a height of the extension section by a height of the helical groove into which the base section is fitted, so that the heat exchange area of the fin can be increased.

Second, the fin is formed into the base and extension sections such that the base section is in surface contact with the outer surface of the tube, so that the surface contact area can be increased to enhance the heat-exchange efficiency.

Third, the base section of the fin is fitted into the helical groove of the tube, and thus the fin is prevented from running idle on the outer surface of the tube, so that the fin can be stably joined with the tube.

Fourth, the base section being in surface contact with the tube is formed on the fin, and simultaneously the first extension section bent outward in a radial direction of the tube and the second extension section bent along the tube bending section that is region where the tube is to be bent are previously formed, so that the bending load generated when the turn-fin tube is bent can be reduced to provide excellent machinability. In other words, the extension section to be disposed on the tube bending section is previously machined into the first and second extension sections, so that it is possible to reduce a possibility of the tube being crushed or damaged when the turn-fin tube is bent, a fraction defective of the turn-fin tube, and the cost of production of the turn-fin tube.

Fifth, the extension section is previously formed into the first and second extension sections on the tube bending section of the turn-fin tube, so that it is possible to reduce the bending load when the turn-fin tube is bent and to increase the heat-exchange efficiency. In detail, the extension section may be cut off to reduce the bending load when the turn-fin tube is bent. However, since the extension section is not cut off in the exemplary embodiments, it is possible to increase the heat transfer efficiency as well as the machinability.

Sixth, in the process of inserting the bent turn-fin tube into the bracket in order to fix the bent turn-fin tube, the second extension is bent, so that the fin can be prevented from being damaged, and the turn-fin tube can be smoothly inserted.

While exemplary embodiments have been disclosed herein, it should be understood that other variations may be possible. Such variations are not to be regarded as a departure from the spirit and scope of exemplary embodiments of the present application, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. 

1-18. (canceled)
 19. A turn-fin tube comprising: a tube capable of channeling a flowing fluid; and a fin wound in a helical shape on an outer surface of the tube, wherein the fin includes a base section wound on an outer surface in contact with the tube, and an extension section extending from the base section at a predetermined angle in an outward direction from the tube.
 20. The turn-fin tube according to claim 19, wherein the tube has a helical groove formed in a helical shape in a lengthwise direction thereof, and the base section is fitted into the helical groove.
 21. The turn-fin tube according to claim 19, wherein the extension section includes a first extension section, which extends in the outward direction of the tube, and a second extension section, which is bent at the first extension section in a lengthwise direction of the tube, on a tube bending section where the tube is bent.
 22. The turn-fin tube according to claim 20, wherein the extension section located on a tube bending section where the tube is bent is installed in a state in which at least a part thereof is cut off.
 23. An apparatus for manufacturing a turn-fin tube, comprising: a tube supplying unit configured to supply a hollow tube; a strip supply unit configured to supply a strip; and a groove forming unit configured to form the strip into a fin wound on an outer surface of the tube in a helical shape, where the fin includes a base section provided on a surface in contact with the tube, and an extension section extending from the base section in an outward direction of the tube at a predetermined angle.
 24. The apparatus according to claim 23, further comprising a groove forming unit, which is configured to press an outer surface of the tube to form a helical groove in a lengthwise direction of the tube such that the base section can be fitted into the helical groove.
 25. The apparatus according to claim 23, further comprising a pressing unit, which is configured to press the extension section located on a tube bending section where the tube is bent so as to have a first extension section, which extends from the base section in an outward direction of the tube at a predetermined angle, and a second bending section, which is bent at the first extension section in a lengthwise direction of the tube.
 26. The apparatus according to claim 24, wherein the groove forming unit includes: a pressing roller having a pressing blade configured to press the tube to form the helical groove in the lengthwise direction of the tube that is configured to be rotated and linearly transferred; and a supporting roller assembly having supporting rollers, which are configured to be co-rotated in a rotational direction of the tube and support the tube on one diametrical side of the tube when the pressing blade presses the tube on the other diametrical side of the tube while being rotated.
 27. The apparatus according to claim 26, wherein the groove forming unit further includes a roller assembly moving unit, which is configured to move the supporting roller assembly in a vertical direction.
 28. The apparatus according to claim 26, wherein the groove forming unit further includes a tilting unit, which is configured to tilt the pressing blade to change a contact angle between the pressing blade and the outer surface of the tube.
 29. The apparatus according to claim 23, further comprising a cutting unit configured to cut at least a part of the extension section located on a tube bending section where the tube is bent.
 30. A method of manufacturing a turn-fin tube, comprising: supplying a hollow tube; supplying a strip; forming the strip into a fin, the fin having a base section installed on a surface in contact with the tube and an extension section extending from the base section in an outward direction of the tube at a predetermined angle; and winding the fin in a helical shape on an outer surface of the tube to form the turn-fin tube.
 31. The method according to claim 30, further comprising pressing the outer surface of the tube to form a helical groove in a lengthwise direction of the tube such that the base section can be fitted into the helical groove.
 32. The method according to claim 30, further comprising pressing the extension section located on a tube bending section where the tube is bent so as to have a first extension section, which extends from the base section in an outward direction of the tube at a predetermined angle, and a second extension section, which is bent at the first extension section in a lengthwise direction of the tube.
 33. The method according to claim 31, wherein the forming of the helical groove includes: rotating and linearly transferring the tube; bringing supporting rollers, which are rotated corresponding to a rotational direction of the tube, in contact with the tube on a diametrical upper outer surface of the tube; and pressing a diametrical lower outer surface of the tube using a rotating pressing blade in order to press the tube to form a helical groove in a lengthwise direction of the tube.
 34. The method according to claim 33, wherein the forming of the helical groove further includes tilting the pressing blade to change a contact angle between the pressing blade and the outer surface of the tube.
 35. The method according to claim 30, further comprising cutting at least a part of the extension section located on a tube bending section where the tube is bent.
 36. A turn-fin type heat exchanger comprising a turn-fin tube according to claim 19 and a bracket supporting the turn-fin tube.
 37. A turn-fin type heat exchanger comprising a turn-fin tube according to claim 20 and a bracket supporting the turn-fin tube.
 38. A turn-fin type heat exchanger comprising a turn-fin tube according to claim 21 and a bracket supporting the turn-fin tube.
 39. A turn-fin type heat exchanger comprising a turn-fin tube according to claim 22 and a bracket supporting the turn-fin tube. 